Allow user to create branch when committing changes

When a user opens a project in the multi-file editor and makes changes, they may want to commit them to a new branch with the intention of later opening a merge request.

Proposal

Allow a person using the multi-file editor to create a new branch with they create the commit. They should be able to choose the name of the branch to match their preferred or organization mandated naming scheme.

Design

• By default wider sidebar, so we can have a bigger commit message field
• Explicit options:
  • Commit to current branch
  • Create a new branch and continue editing (shifting the Web IDE to the new branch)
  • Create a new branch and a new merge request, discontinue editing, and go to the newly created merge request (is automatically configured to merge into the original branch)
• Question icons feature tooltips explaining flow after hitting commit
• branch-field is auto-pre-filled with syntax: [username]-[branchname]-patch-[i]